Worklets

nitroFetchOnWorklet() lets you run parsing/mapping off the JS thread using react-native-worklets. This is useful to parse data without blocking the main JS thread.

Setup

1. Install the package

npm install react-native-worklets

2. Add the Babel plugin

Add the Worklets babel plugin to your babel.config.js:

module.exports = {
  presets: ['module:@react-native/babel-preset'],
  plugins: [
    // ... other plugins
    'react-native-worklets/plugin',
  ],
};

tip

Since Expo SDK 54, the Expo starter template includes the Worklets babel plugin by default — you can skip this step.

3. Install native dependencies

# iOS
cd ios && pod install && cd ..

# Clear Metro cache
npm start -- --reset-cache

Usage

import { nitroFetchOnWorklet } from 'react-native-nitro-fetch';

const map = (payload: { bodyString?: string }) => {
  'worklet';
  return JSON.parse(payload.bodyString ?? '{}');
};

const data = await nitroFetchOnWorklet(
  'https://httpbin.org/get',
  undefined,
  map,
  { preferBytes: false }
);

Options

Option	Default	Description
preferBytes	false	When true, sends bodyBytes to the mapper; when false, sends bodyString
runtimeName	—	Optional name for the created worklet runtime

For more details, see the full react-native-worklets documentation.